CAP Comprehensive Chemistry. Serum iron survey

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Analytical Chemistry

Background:

• Serum iron determination is crucial for diagnosing various health conditions.
• Variability in laboratory methods can lead to discrepancies in results.
• Standardization of serum iron assays is essential for reliable clinical interpretation.

Purpose of the Study:

• To investigate the impact of different laboratory practices on serum iron determination results.
• To identify factors contributing to variability in serum iron measurements.
• To provide insights into optimizing serum iron assay methodologies.

Main Methods:

• A questionnaire was distributed to approximately 1,600 laboratories regarding their serum iron determination protocols.
• Data collected covered sample preparation, analytical systems, detection methods, reducing reagents, and standards.
• Reported serum iron values were analyzed based on the different methodological categories.

Main Results:

• Laboratories using AutoAnalyzer methods reported consistently higher serum iron values.
• Methods excluding protein removal yielded the lowest reported serum iron values.
• Hydroxylamine as a reducing reagent was associated with lower reported results.
• No significant difference in results was observed between common chromogenic reagents (bathophenanthrolene sulfonate, tripyridyl-triazine, ferrozine).

Conclusions:

• Methodological choices in sample preparation and analytical systems significantly influence serum iron determination.
• Protein removal and specific reagents like hydroxylamine can bias results.
• The use of protein-based standards is recommended for methods affected by protein.
• Establishing a definitive method for accurate serum iron assay value determination remains an unresolved challenge.